Hi @Amy Espinosa , welcome to Q&A forum!
If the users don’t have O365 accounts and want to access the content in the SharePoint Online site, yes we can use external sharing. And the content of SPO are all stored in the servers of Microsoft which cannot be accessed by external factors, so usually the driver on your servers will not affect SPO.
In addition, SPO is also very cautious about the permission level. You can give external users the permission level you want.
For more information about how to use external sharing you could refer to:
External sharing overview
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