Both "form friends" and "make friends" are commonly used phrases, but "make friends" is more commonly used and considered the standard phrase in English.
When we say "make friends," it means to establish or develop new friendships with people. It is a straightforward and widely understood expression.
On the other hand, "form friends" can be grammatically correct, but it is less commonly used in everyday language. It might be interpreted as slightly less natural or less idiomatic compared to "make friends."
So, to answer your question, "make friends" is the more correct and widely accepted phrase to use when referring to the process of developing new friendships.