To clarify on this, the default that a player can have access to is 3 bios in total. This number was at one point restricted in milestones that were unlocked after progressing through the ranks, such as 1 to start, 2 after Chunin then 3 after Jounin. But as far as I can tell, this restriction doesn't really seem to be a thing anymore, at least not that I can tell.
As for the max possible number of bios, 3 is the "free default," let's say, but there is now a new addition to the shop to purchase an additional bio slot with Kumi. As mentioned in the latest role-play announcement, there isn't an officially declared limit to how many of these can be purchased as of yet given that it is a newer system, but keep in mind it absolutely isn't intended to be limitless. But at least the option is there now.
So to summarize, at the starting rank of Academy Student, it isn't unreasonable to suspect you could make more than one bio if desired, but I personally would advise against doing so, since the goal is to develop a grow your overall rank and arsenal in a steady proactive fashion, which is best to do with a single biography starting out. Its easier and less labor to update one bio each rank up, than 3 bios each rank up.
