I am Doordash driver, I do minor handyman jobs and I do laser engraving. Can these 3 things be under 1 LLC or do I need 3 separate ones?

It depends on the type of business structure you choose for your LLC. If you choose a single-member LLC, then all three businesses can be under one LLC. However, if you choose a multi-member LLC, then you will need to create separate LLCs for each business.