Deepening on where you are you need 15-20 days left on your stay to apply for non-o 90 days. You can extend 30 said if need more Time.
Go immigation and get that local updated info for the visa and what papers you need, if you don't know. Expect that wondering will be missing and come back again...
Money need to be in the bank, potentially weird from abroad ,(retirement) before to apply to move to 90d non-o visa. And you need to have 15-20 (depends where) days left on your current legal stay when you apply.