how to remove a field in a form template

To remove a field, just click on the field, which will show you a red recycle bin icon to delete it.

Please note that if you have a live form, DO NOT DELETE the field. If you delete the field, all associated submissions in that field will also be deleted. In such a scenario, instead of deleting, please HIDE the field. To Hide, just right click on the field, which will give you an option to HIDE the field.

Hope this answers your query.