Hi @AnnTaxed! Thanks for writing in with your question today.
You are allowed to save receipts in any format and location that works for you, whether that's a cloud drive, file folder or shoebox. The important consideration is that if you were ever audited and needed to provide receipts to the auditor, that the receipts could be accessed and would be in readable condition. If you are audited, you will need to provide paper documentation to the auditor. The IRS is not going to accept emailed files or a link to your cloud storage. So you're fine to save them in cloud storage as long as you're willing to print them out in the unlikely event you need to prove an expense. (And make sure your cloud storage provider is safe and reliable too).
I hope this helps answer your question!