Are you self-employed? 
Please contact your customer advisor and provide them with the company number to which invoices/due date notifications may be sent via Peppol.
You can find the contact details of your personal customer advisor on My Liantis under the Contact tab. All relevant details, including the contact information of your customer advisor, are also listed at the top of your invoices and due date notifications.
You can have your invoices sent digitally by setting this up on My Liantis, as explained in 'How can I receive my invoices digitally as a self-employed person?'. 

Please note: this is not yet possible for the company contribution.

Are you an employer?
Then you can have this set up by your accountant and/or your trusted customer advisor at Liantis.
You can find the contact details of your personal customer advisor on My Liantis under the Contact theme.

Via the links below you will find more information about sending and receiving invoices via Peppol:
Peppol | Liantis
Meestgestelde vragen | Peppol | Liantis
FPS Policy and Support
Is my company covered by the B2B e-invoicing obligation? - e-invoice