I have a list of primers in an Excel file. Can I import those primers into SnapGene?

You will need to export the primers to a delimited list. In Excel, list the primers with a Name column and a Sequence column, plus an optional Notes column. Export the data by using Save As with the format Tab Delimited Text. Then in SnapGene, use Primers → Import Primers from a List.

See this User Guide article for more information – Import Primers.