While much more can be said on this subject, perhaps you'd enjoy these previous answers from AskHistorians users:

Here is an answer where, /u/shlin28 and /u/cptbuck respond to a book called 'Islam and the future of tolerance: A Dialoge,' namely the parts of the book where one of the authors asserts that Islam was primarily spread through violence.

Here is another answer from /u/frogbrooks and /u/sunagainstgold which discusses whether the spread of Islam was violent or not, focusing especially on the initial Caliphate regimes arising from the Arabian peninsula.

And here is an answer that focuses on the spread of Islam to Southeast Asia, demonstrating the diversity of ways in which religion spread, written by /u/pangerandipanagara