MySQL workbench : How to export mysql database to .sql file?

In MySql Workbench version 8.0 you can just follow the next steps

1. Go to Server tab
2. Go to Database Export

This opens up something like this

3. Select the schema to export in the Tables to export
4. Click on Export to Self-Contained file
5. Check if Advanced Options... are exactly as you want the export
6. Click the button Start Export

try this and select export to self constrained file .sql along with the path.