how do i create a saved search to show all the VAT/GST collected per month?

Look at SA 64710, you should be able to modify based on your needs.

can that report be transformed into a similar saved search?

you might be able to, some report you can, whats the issue with report? if you don't mind me asking

i was not able to find any report using that SA64710 that gave me total VAT or GST that has been collected

I don't have VAT Account so i won't be able to test it but this is for Spain VAT Generating and Submitting information, you can look at how they Generate Spain VAT and change your countries and Criteria based on that. Generating and Submitting the Spain VAT Register Information Published 06/09/2017 12:27 AM | Updated 09/16/2019 09:38 AM | Answer Id: 64710

i dont see Tax > Tax Audit Files under Reports

hmm i don't know I can't help with you that as I don't have VAT accounts, I have US Sales Tax report.

Tax Audit files comes with the Audit File SuiteApp

thank you!