SharePoint column dates

jonna1973 To answer your first question, create a caclulated column for column 2 with a formula similar to "=DATE(YEAR([Column1])+3,MONTH([Column1]),DAY([Column1]))"

See other formula options at https://support.microsoft.com/en-us/office/examples-of-common-formulas-in-lists-d81f5f21-2b4e-45ce-b170-bf7ebf6988b3 

For the second part, create a Power Automate Flow the runs daily (reoccurrence) that gets the list items where column 2 equals today PLUS 30 days and set the action on the results to send the email.

Read through the following article for some examples: https://powerusers.microsoft.com/t5/Building-Flows/Trigger-a-flow-on-a-date-value-from-a-Sharepoint-list/td-p/30305 

Other Reference: https://docs.microsoft.com/en-us/power-automate/run-scheduled-tasks

This should get you started down the right path. If this helps, please consider marking it as the solution. -Don