I'm trying to create/edit a tasks list, so that when i click "new", it will be possible to first select company from a lookup column pointing to a standard contact list, and then select an employe (full name), based on what company was selected.
Basically i'm trying to create a tasks list which, we can use to track phone and remote support incidents, for later invoicing..
And i want people to be able to select both the company and the employe they have spoken with.
When i click new or edit form, i can only se the "base" field not the additional fields, the additional fields do pop up afterwards i the list display.
I know i could create a "Company" list, and get data from this, but i want the contact list i select from, to be able to integrate into Outlook, and custom list's doesn't integrate very well..
Your best bet would be to wait till you get the new PowerApp integration in your tenant here in the next month and use a custom list instead of a task list(so you get modern UI experience). Then you can use powerapps to tie into other systems etc. using connectors and customize the form with Cascading drop downs based on company which will filter the person your picking from etc.
Right now out of the box you really don't have that option. You could technically use infopath as well, but that isn't something you would want to invest in since it's being deprecated.
If you can't wait that might be your only option, but Powerapps is about to be pretty powerful and useful once the SharePoint integration is turned on.