The government has published a law on electronic invoice transactions. However, there is no obligation yet. The Federal Law No.1 of 2006 on Electronic Commerce and Transactions introduced the regulation of electronic account documents, records, and validation processes like authorization, and signature. With the Federal Legislative Decree No. 8 of 2017 regulation reminded. When e-Invoice becomes mandatory, according to these laws, invoices will have to be generated and sent only in electronic format, an electronic signature will be mandatory and there will be a ten-year archiving obligation.
Unlike e-Invoice, VAT Return filing is mandatory for all VAT registered taxpayers from 2018. All responsible businesses must submit their online VAT return periodically. VAT returns are generally submitted quarterly exclude some companies that upload monthly due to their tax period. UAE’s Tax Authority is closely following the transition process of KSA’s gradual implementation of e-Invoices to its systems. Updates are expected on e-Invoicing obligation in the UAE as of 2022.
You can find the details about KSA’s mandatory e-Invoicing process, which will come into effect as of 4 December here; https://snitechnology.net/saudi-arabia-electronic-invoicing/