Relevant Products: Exclaimer Cloud Signatures for Office 365 | Exclaimer Cloud Signatures for G Suite
You are using Exclaimer Cloud on a web browser, but the drag and drop editor will not allow you to add anything onto or remove anything from the template design.
Typically this issue is caused by add on's or extensions installed in the browser, or just general security settings that prevent the editor from working correctly.
Login to the Exclaimer Cloud portal using an incognito browser window, or an alternative browser. If you have any extensions installed in your default browser, this may be the cause. To determine which extension is the cause, disable them one by one and retest.