Home Garden Seedlings - Sourcing

Hi all- new time gardener here. Hoping to build a small one this year but don’t want to introduce anything invasive. How can I source seedlings and plants that aren’t invasive / imported from afar? Sorry if this question doesn’t make a lot of sense - I just want to do it right while making sure it’s a fully organic practice and conscientious of the environment I’m in. Thank you!