Bahagi = share
Makibahagi = to share

The most commonly used form of the word "sharing" in Tagalog is "pakikipaghati", from the root word "hati" which literally means "to divide". The alternative form "paghahati-hati" may also used especially in situations when there are many parties involved in the act of sharing.

When a Tagalog speaker wants to convey "share this with him/her", that speaker says "hatian mo siya".

A derivative or alternative would be "bahagian", which means "to distribute or dole out a split-up portion". However, please note that this is more particularly used to convey the kind of sharing that includes a concept of "separation" (e.g. a loaf of bread was cut into several pieces and each person got his own piece).

In comparison, the kind of sharing conveyed by "pakikipaghati" is more of the "mutual or communal" kind (e.g. a loaf of bread was not cut into several pieces, but instead was passed around for everybody to bite into it).

I hope you do get the distinction between these two, and you may choose whichever kind of "sharing" you wish to convey...

Hope this helps!

pagbabahagi - sharing (present participle)
ibahagi - share (root word/noun)

Give a portion of (something) to another or others