Answer:
I think your talking about Brainly Plus, so here's the instructions:
1. Visit your account settings.
2. Click “Cancel Subscription.”
3. You can continue to use subscription benefits until the end of your billing period.
4. After your renewal date has passed, you’ll still have access to your content.
If your talking about deleting your account in general, here's the instructions as well:
1. Visit your account profile settings.
2. In the Privacy section, click the “Delete Account” button.