Create a custom field

1. Go to Settings > Custom fields
2. Click on Create new custom field
3. Fill the details of the custom field and save clicking on Create custom field

Edit a custom field

1. Go to Settings > Custom fields
2. Click on the custom field you want to edit
3. Click on … / Actions > Edit custom field
4. Edit the details of the custom field and click on Save changes

Edit a custom field on an object

1. Select the object you want to edit
2. Click on … / Actions > Edit custom fields
3. Edit the custom fields and click on Save changes