You should read Contacts Overview to have a good understanding of what Contacts do in Docketbook.
Docketbook Contacts can only be accessed and maintained from from the PC web user interface
As explained in the Contacts Overview, email addresses are key identifiers in Docketbook, both for people (Docketbook Account holders) and the Organisations (Companies) they are associated with. For company to company communications we use a special 'on.docketbook.io' address. This is a unique email address that identifies your company, or organisational unit, on Docketbook. The sending of Contact Details creates the relationships that enable Assigning, Sending and Sharing Orders, Jobs and Dockets.
Contact Shares are how other Docketbook users and Organisations seek to create a relationship with you, to start using Orders, Jobs and Dockets with you.
How to accept a Contact Share
Contact Shares sent by others will appear in the Dashboard area of My Docketbook for shares sent directly to your email address or in the Dashboard area of the Organisational unit for Company shares.
To accept the Contact Share click on the Notification to open it.
Check the details and either click on Create New Contact or Add to Existing Contact.
Once you have accepted the Contact Share, delete the notification. You can then go into Contacts to Share your Docketbook Details back to that Company.