How to create a custom field for modules?

Hello Hubspot-Community,
I’m trying to add two custom fields to the modules, which are supposed to set the Top and Bot margins of the Modules. Those margins are the same across all 30+ Modules and it would be a blessing if I could add a custom field, so I only have to select the field without editing anything.
I added a custom field to the fields.json but somehow it’s not showing in die Add-Field-Select Dropdown Menu when I create custom modules.
Does anyone have experience with that and could help me?
That what i added to .json:

{
“name”: “Spacing_Top”,
“label”: “Spacing-Top”,
“required”: true,
“locked”: false,
“Multiple”:“false”,
“display”: “select”,
“choices” : [ [ ", “No Spacing” ],[ “module-spacing-md-top”, “Medium Spacing (5rem)” ], [ “module-spacing-lg-top”, “Large Spacing (7.5rem)” ] ],
“type”: “choice”,
“default”: “module-spacing-lg-top”
},
Best regards,
Joshua

To add some futher information:
Currently im fetching my modules and im Copy/Paste those fields.json into the other modules.
So my question is: Is there a way to make those fields available as a preset, so i can choose the field like i choose a normal field like the text field.

@joshuamiller

In your choices, the value of the first choice is not declared correctly. Your value should be in double quotes like this “value” & and your .json should be like this:-

{
 "label": "Spacing-Top",
 "name": "spacing_top",
 "type": "choice",
 "sortable": false,
 "display": "select",
 "choices": [
 [
 ",",
 "No Spacing"
 ],
 [
 "module-spacing-md-top",
 "Medium Spacing (5rem)"
 ],
 [
 "module-spacing-lg-top",
 "Large Spacing (7.5rem)"
 ]
 ],
 "default": "module-spacing-lg-top"
 }

And this is how it will show. (CLICK HERE)

You can’t create presets for your fields but there is also a choice field that you can use for the same purpose.

I hope this will help you out. Please mark it as Solution Accepted and upvote to help another Community member.
Thanks!