At the beginning, relationships between Spain and other countries were by no means good. Western countries and specially USA and the USSR viewed Spain as a remnant of the losing side of WW2 and it was not even invited to the Conference of San Francisco (which gave birth to the Charter of the United Nations).

Resolution 39 of the General Assembly, proposed by Poland and passed with 34 votes in favor and 6 against, stablished that Franco's Regime was a fascist goverment helped by nazi germany and Italy during the civil war and that they in return assisted Germany sending the Blue Division and invading Tanger in 1940. As a consequence, the resolution forbid the participation of Spain in all international organizations or conferences held by the UN and even recommended the Security Council to take the necessary measures if in a reasonable time a new legitimate goverment was not established.

In spanish, the period between 1946 and 1950 (sometimes extended until 1955) is called "la cuestión española" and is regarded as a time in which totalitary regimes were not accepted by the international community. It is also worth noting that many spanish republicans fled during the civil war and established themselves in latinamerican countries, even participating in the conference of San Francisco trough the influence they exerted over some delegations.

However, things changed in the following years because the international community concentrated in the new menace posed by communism (considering that the Chinese Revolution and the corean war occured during those last years of the decade). Now having a "strong" government with deep catholic and anti-communist roots was, so to say, a necessary evil and a realiable ally in terms of condemning anything "red". Again, a resolution of the General Assembly is an important piece of history to understand how things changed: Resolution 386 of 1950 passed with 38 votes in favor and paved the way for spanish acceptance in the UN in 1955. Still, it is important to note that France and UK abstained and some latin countries like México, Guatemala and Uruguay voted against, as well as Israel and (of course) the soviet republics.

Sorry for any mistakes, english is not my first language.

If you are fluent in spanish (I'm not sure if they have subtitles) DMAX Spain made a series of documentaries on Franco, from his ascendance to his death and the transition of power at the end of the regime.

Sources: i'll look at some sources in english. At the moment, I recommend you taking a look at the UN resolutions and an article called "Overruled and Worn Down" by Mark S. Byrnes and the book "Truman, Franco's Spain and the Cold War" by Wayne H. Bowen.