if I am keeping my current iphone but transferring to another carrier do I need to delete all my info from the sims card and reinstall it??

Welcome to Apple Support Communities.

The info on your iPhone and the SIM card are two unrelated things. You can switch the SIM card and all the other data (contacts, photos, etc.) will stay. The only thing that might not stay is Voicemails. Depending on your situation, your phone number might change.

-Jack

Iphones don't store anything on the sim card

The SIM card is only for one cellular carrier.

If you switch to another carrier, you need a SIM card from them