Can I import accounts from an Excel spreadsheet or csv ?.

You would need to use the Data Migration Framework (DMF) for the correct approach

There is an alternative but it is going to be time consuming if there are a lot of Accounts. That is to import them as Leads and then to convert them to Accounts. However, each Lead needs to be manually converted to the Account and the Lead record type would not have as much information associated with it. Also, if you then decide to delete the Leads you need to remove the Originating Lead field value in the Account first.