In the WP Leaflet map plugin, metabox is used to create locations in the map from post and page. By default, metabox enables in your Leaflet 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 the ‘WP Leaflet Map Pro’ box.

Then you’ll see metabox hide from your posts or pages.

From Leaflet map setting

Step 1: Go to WP Leaflet map > Setting.
Step 2: Mark the checkbox of ‘Posts’ and ‘Pages’ in the ‘Hide Meta Box’ option.

Step 3: Then click Save Settings. Now you’ll see metabox hide from your Posts and pages.