Mailflow has two plans. There is the free plan with a maximum of 50 email threads, and there is the paid plan with unlimited threads.
Step 1 – Click on Mailflow in the left-hand menu
Step 2 – Open Account settings.
Step 3 – Click Upgrade.
Step 4 – Enter your billing details and click Subscribe.
You can downgrade your plan to free at any time. You will no longer be able to add emails to Mailflow or access info in your projects until you update again or delete projects until you are below the 50 email limit.
You can downgrade by going to your account as described above, clicking billing, and then Cancel plan.