Currently there are three different features for you to create custom action buttons for your sheet design.
The following sections will show you how to do these through the Custom Buttons that could be found under the Design Mode, within the Form Tools menu.
These methods are:
You can also edit the existing custom buttons through the Custom Buttons section > click on the action button name > adjust your configuration of the button > Save design changes.
There are some additional settings you can configure for action buttons, you may refer to this article for detailed information.
If you want to remove the buttons you don't need anymore, you can refer to this article.