In order to add a custom field to a client / contact, via the Contacts, Web Portal > CRM > Contacts > Edit pencil > Add Custom Field.
(Note: You can also go to the People tab inside your contact card > select the Contact you wish to add the field to > Edit pencil > add the Custom Field if you don't want it added to the Billing details).
To create Contact Variables, go to the Settings cog > Contacts > Contact Custom Fields. These are variable fields relating to a contact for example birthday or any else you would like to capture about the contact. A Client variable can be selected to be searchable in the contacts list.
Please note that the custom variable that is added, is only set to the specific Client / Contact within a Billing Name. For the information to be used for more than one Contact that is under the same Billing Name, the information will need to be added to each of those Contacts that it is required for, otherwise it will not pull across to form fields.
To create Location Variables > Settings cog > Contacts > Location Custom Fields. This is specific information about the location itself. A location variable can not be selected to be searchable in the contacts list. As with the Client / Contact variables above, information added to a Location variable will only be related to the Location that's been selected / edited. To add the information to other Locations, you will need to manually add the information to each of them.
NOTE: Custom Variables are only able to be pulled in through a form and visible on the contact card. If you are looking to store information on a location such as the Gate Access code, this information would be better stored as a Client or Location note which is easily visible on the App in the job.