Can I append the domain name part of an email address automatically?

(2) Also is there a way to auto-fill the end of an email extension? Meaning if the user starts to type their name [name]@gene.com or [name]@roche.com - can there be a prompt for the @gene.com OR @roche.com to auto-fill. 

I'm not sure how you want this to work exactly but I'm thinking this is achievable by using Conditions.

Here's a demo form I came up with: https://form.jotform.com/63547685232967 Is that what you're aiming to do?

e.g.

1. User fills out a textbox with their name

2. An email address will automatically be generated with a specific domain (e.g. @gene.com)

If so, just setup your condition as follows:

Related guide: Smart-Forms-Using-Conditional-Logic 

Some pointers when setting up the Calculation part of the Condition:

a. Clicking a field will toggle its background color (brown/black)

b. Brown denotes a text while Black denotes a number

c. Since we're just manipulating texts, ensure everything has a brown bg by clicking on it

d. You can just type in @gene.com straight on the box above > then press the Tab Key on your keyboard

In case we misunderstood your question, just get back to us with a bit more info and a clearer description of what you're trying to do so we can better assist you.