I assume you are talking about whether or not the Buddha was a real person. While I'm not a scholar, historian, or Buddhist. I am keenly interested in this subject and can, at the very least, give some context.
The traditional Buddhist narrative tells us that the Buddha (which means something like Enlightened or Awakened One) was born in the mid 6th century BCE in modern day Nepal to a king and his main wife of the Sakya clan (we now know them to have been an oligarchic republic so the Buddha's father was probably an elected head chief) and given the name Siddhartha Gotama. At age 29 he fled his family home in search of enlightenment, abandoning his title, family (including a young son), and wealth. He joined a group of wandering ascetics but became disillusioned with them and sought his own path to enlightenment, which he achieved after 49 days of fasting underneath a tree at the age of 35. He spent the next 45 years of his life as a wandering preacher throughout Northern India and died at age 80 after falling ill. OR at least that is how it is traditionally told.
As far as primary sources from that period and archeological evidence, we have little to nothing that we can definitely associate with the Buddha or the sangha during his life or shortly after. Most people during the Buddha's time were entirely illiterate and what writing DID exist was far out of the reach of most of their audience, writing in India wouldn't come into prominence for 2 or 3 centuries after the Buddha. That said, not to long after the death of the Buddha, we begin to see Stupas (buildings meant for Buddhist relics) built and pictographs of Jataka tales (tales of the Buddha's past lives, many of which were adapted from and into fables) appear.
Our most important sources are contained in the early canonical texts of Buddhism, namely the Pali canon and the other early sectarian Buddhist canons preserved in fragments and translations. While these texts were written down during the final century B.C.E., the dialect and consistency between the suggests that they were in fact composed much earlier, perhaps only a few decades after the death of the Buddha.
It may seem strange then, given that all we have are oral records from the era of the Buddha (from his own followers no less!), that the Buddha is generally agreed to have been a real person. But it isn't just the Buddhist records that mention him, Buddha also appears in Hindu and Jain sources as well, often in debate or for Mahavira to refute him (though never so directly as Gosala, the founder of Ajivikism).
The Buddha was a Samana (lit. Seeker), one of many wandering mendicants who taught new philosophies and founded religious movements, many of them were quite important and often encountered and mentioned one another. The Pali canon mentions at least six others, some of which had long since disappeared by the time it was committed to writing. Had one of these Samanas not existed, refuting them would be considerably easier by casting doubt onto their existence, especially since a healthy degree of skepticism is part of many of these traditions yet they all, well Jainism and a few Vedic traditions are all that survive aside from Buddhism so we can't say that with absolute certainty, accept that their founders were real and interacted with each other.
Earlier, I mentioned that we can say with at least some certainty that the Pali Canon is certainly older than the first century B.C.E. when it was written down, though certain books are probably later editions (the abidhama in particular appears to have been composed later), but neglected to mention specifics. Essentially, language experts have analyzed the language in the Pali Canon and compared it both internally and externally to other documents and found that the language used in the Sutta Pitaka and Vinya Pitaka (the first two "baskets" of the Tipitaka in pali) is far older than its written form (the final book, the Abidhamma Pitaka, appears to be an addition to help explain the Suttas more complicated teachings and to expand upon those as well). Additionally, comparisons with the Tibetan, Chinese, and fragmentary bits of what is left from the other Indian sects of Buddhism gives us some clear similarities that we wouldn't expect from works that didn't have an origin before the major splits in Buddhism (Buddhism divided into several (at least 18) schools following the reign of Ashoka in the third century BCE; the Pali Canon, Chinese Canon, and Tibetan Canon are all descendants of different sects though the Tibetan and Chinese canon broadly fall under the same lineage). We also have a few scattered quotations and lines in tombs, stupas, rocks, and caves dating back to at least Ashoka showing the general teachings. From all this, we can assume that at least some of the Suttas appear to date back to shortly after the Buddha's death, at most a century, and came from a small group of people, perhaps interpreting or trying to remember exactly the teachings of one person, due to their internally consistent logic, language, and teachings.
So we really do only have the scriptures of the various canons to confirm the Buddha's existence, along with maybe a few other references in other religions works, but there is verifiable information in that canon and indicates a very real person behind it all. Wrapped in layers of mystique and exaggeration, yes, but at the end of the day, it seems likely that there is at least some truth behind the person we now know as Sakyamuni Gotama Buddha.
Sources:
Edited for clarity and consistantly Pali spelling as opposed to the slapdash mixture of Pali and Sanskrit transliteration. I speak no Sanskrit and very, very limited Pali so if there arr errors in my translation or transcription feel free to correct.