Deleted emails via mail app but it still shows unread in gmail inbox

Hi cynd921,

For help with deleting an email, check the steps below and settings on your iPhone to ensure you have messages going to the trash and not being archived. The guide here has the information as well: Delete and recover emails in Mail on iPhone

"Archive instead of delete

Instead of deleting emails, you can archive them in the Archive mailbox.

1. Go to Settings  > Mail, then tap Accounts.
2. Do one of the following:

• If you’re using an iCloud email account: Tap iCloud, tap iCloud again, tap iCloud Mail, then tap iCloud Mail Settings.
• If you’re using another email account: Tap your email provider, then tap your email account.

1. Tap Advanced, then change the destination mailbox for discarded emails to the Archive mailbox.

When this option is turned on, to delete an email instead of archiving it, touch and hold , then tap Trash Message."

You can also find helpful information here: Delete emails on your iPhone, iPad, and iPod touch - Apple Support

Cheers.