Microsoft access to Sql Server Data Migration
I would use the SQL Server import wizard, but make sure to use staging tables to import the data from Access, so you can perform data cleansing before inserting on the definitive tables.

A staging table is a temporary table used to load the data "as is" in the destination system (SQL Server in your case) so you can make sure the datatypes, collation, any custom format is according to your needs. This is made to avoid key/constraint violations, errors due to incompatible datypes, etc...

So for this example, you can import your access tables and ask the wizard to create the new tables during the import, after your are ok with your data, you can insert them in your definitive tables.