We can send invoices via postal mail by using Lob.com
The Lob credentials are shared in the Office folder in the Keeper vault.
How to send a document via Postal Mail using Lob
From the Lob dashboard, Print & Mail > Letters.
Click the Live button at the top. Then click Create a Letter:
On the next screen, choose Operational as the Use Type. Add the description and address. Set the From address to GEEK GIRLS IT SERVICES.
Upload the PDF you want to mail. (If you are sending an invoice, you can generate a PDF from Quickbooks.)
Choose black and white unless color is truly needed. (Color is more expensive.)
Choose two-sided unless one-sided is truly needed.
Click create. You will be taken to the status page where you can see what the mail item will look like. You have completed the process.
In the preview the return address generated by the system may cover our logo. This is acceptable for sending invoices, as long as the recipient's name and address are visible.

Make sure there are enough Lob credits for the mail piece to go out. You can check this under Billing.
How to See Postal Letters that were Sent Using Lob (Used for customers that prefer snail mail invoices)
Log into the dashboard. (There is only one account. the credentials are stored in the OFFICE folder of Keeper.)
Click on Letters under Print and Mail to view status of mail. Click on the item you want to view.
Tracking Certified Mail
Lob provides the tracking number in the Lob dashboard for relevant mail pieces, such as Certified Mail. You can also find tracking numbers included in exported mail data CSV files from the dashboard.
Pricing for Lob Services
We are on the free (developer) plan. Our invoice is usage-based.