In the WP Google map plugin metabox are used to create locations in map from post and page. By default metabox enable in your Google map plugin.You can hide meta box from post and page in 2 ways:
From Posts or Pages
Step 1 Go to Posts or Pages in the dashboard.
Step 2 You need to use the screen options at the top of the posts/pages and unmark ‘WP Google Map Pro’ box.
Then you’ll see metabox hide from your posts or pages.
From Google map setting
Step 1 Go to WP Google map > Setting.
Step 2 Mark the checkbox of ‘Posts’ and ‘Pages’ in ‘Hide Meta Box’ option.
Step 3 Then click Save Settings. Now you’ll see metabox hide from your Posts and pages.