Removing unnecessary tabs
Your Gmail inbox has several tabs like Starred Basic, Social, Campaigns, Snooze, Forums, and more. All these tabs are not required by users. So disabling them will not affect your work. You can also permanently remove your unused tabs. The Basic Email tab does not remove or disable.
Unsubscribing
If you are receiving irrelevant mass emails from senders the only way to stop them is to unsubscribe them. Opening any of the e-mails you receive and then unsubscribing or changing its preference can protect you from such mails. Links to these two options are usually at the bottom of e-mails. If you are unable to unsubscribe you may report those e-mails as spam. Also can block the sender.
Gmail filter
A filter or labels are the best ways to identify unwanted, unimportant, spam e-mails. Options like Inbox, Trash, Sent, etc. are all Gmail labels or filters. After you create a filter for spam and transfer e-mails to it, all spam e-mails appear in this filter. You can easily remove them or ignore them.
Delete email
In order to keep only important emails in your mail box, to free up some space, you should completely delete unwanted emails. Go to Mail Inbox and type in the search bar, then create a label and click the Select All check box. Then tap on 'Delete' option.
Special label
It is also a good idea to delete bulk emails from a specific label. Go to the mail inbox and type a label in the search bar: then select the label name if you want to delete all the unread irrelevant emails. Now click the Select All check box. Then tap on 'Delete' option.
Important messages
The best way to mark important e-mails is to star them. Emails with a star appear faster in Gmail searches. Also you can find them when you need them without spending much time.
