Yes, we support SPF.
You can enable SPF in cPanel. Please see Related Articles below for more information.
Additionally, A2 Hosting can add a custom SPF record to your DNS zone. If you need further assistance, please open a support ticket with our Guru Crew on the Customer Portal at https://my.a2hosting.com. Make sure that you specify in the ticket the exact lines that you want to add to your zone file.