Tableau Desktop is licensed per user. For each Tableau Desktop license, you may install and activate one copy of Tableau Desktop on your primary computer and a second copy on your secondary portable or home computer.
If you are using your Tableau Desktop license on two computers, both can remain activated simultaneously. It is only necessary to deactivate if you need to move one of your copies to another computer
Does Tableau Online provide with embed code for interactive visualisations (similar to Tableau public) and am I allowed to embed to our web site/other web sites?
Yes we can embed code from tableau online as you do it in Tableau public.