Custom Element required

[AHorak]

Hello everyone,

I am looking for a way to define my own elements (placeholders), which I can later replace with values.

e.g. {{Name}} is then later filled with a concrete value

The list of placeholders is predefined.
These placeholders should not be able to be modified, but only added or deleted in the editor.
This placeholder should also be able to be highlighted visually (own style)

Do you have any ideas on how I can do this?