My significant other and I bought a home together this year. She is on the mortgage, I am not. But I'm the one that pays it monthly. Should I click that I bought a home?

Assuming that you are not legally married to each other -

If you are on the deed as an owner of the home then you could claim the mortgage interest as a deduction on your tax return.  If you are not on the deed as an owner, then you cannot deduct the mortgage interest but your significant other can deduct the mortgage interest on their tax return.

It is best that the person on the mortgage (who will get the 1098 reporting form in their name) be the one to claim all the house related deductions ... that leave the other person the standard deduction ... this usually works best for both parties combined and will invite fewer  IRS questions.