Membership Receipts from Civi webform for On Behalf of Organisation
In that case you need to manually add tokens to the receipt - message template  - so you can provide more information to the receipt - 

Creating new tokens - https://wiki.civicrm.org/confluence/display/CRMDOC/Tokens

if you need to add some contact tokens then refer to the below - 
Can I put custom field tokens into a message template?

I guess this helps !!!