You can use your gmail labels in AltaMail to organize your email. To enable gmail labels, open the edit account screen for any gmail account (View) and open the "Advanced" section. Turn on "Gmail Labels".
Gmail Labels will require a bit more network activity to update the labels for emails. Do a manual refresh in the Inbox to check the labels quicker.

There are three ways to set labels for an email after you have activated them in the account settings:

1. Tap on the empty label icon displayed on the right had side of an email in the inbox view
2. Check the check box beside an email and tap on the action button in the top right corner and select "Gmail Labels"
3. Swipe right to left and tap on the "Gmail Labels" option if you have added gmail labels to your swipe actions. View

You can view emails in each gmail label using the "Folders" button in the left side panel. Tap on the gmail folder name to view emails with the label of the same name.

If you want to hide a label from display, use the "Hide Folders" button in the edit account screen (View) - "Advanced" section.

You can use Gmail Labels in email searches, filters and rules.