How to Include Java Script on All Pages in Wordpress

1. Upload your JavaScript file in your theme's folder via an FTP client.
2. Log on to your WordPress site and click on 'Appearance' and 'Editor.'

3. Select 'Header' from the list of templates on the right.
4. Insert the script to include your JavaScript file within the
section of the template:
/pathto/yourscript.js'>
Replace 'pathto/yourscript.js' to the location of your JavaScript file.
5. Click on 'Update File.'