The Zimbabwe Revenue Authority recently wrote a notice ( Notice 97 of 2021) advising members of the public who had recently imported vehicles but could not get plates and registration books that these are now available. They also provided a list of ZIMRA offices where these could be obtained.

Below is the full notice from ZIMRA:

PUBLIC NOTICE:
AVAILABILITY AND ISSUANCE OF MOTOR VEHICLE REGISTRATION BOOKS AND NUMBER PLATES FOR IMPORTED VEHICLES
The Zimbabwe Revenue Authority (ZIMRA) is advising members of the public who in recent months imported motor vehicles and failed to get registration books and number plates, that registration books and vehicle number plates for newly imported vehicles are now in stock.
These can be obtained from the following ZIMRA offices:

Name of office	Location
Beitbridge Border Post	Beitbridge Border Post
Bulawayo Port	Fort Street / 8th Avenue Bulawayo
Harare Port	Ground Floor Kurima House Cnr Nelson Mandela Avenue/4th Street Harare
Gweru	Megawatt Complex Gweru
Masvingo	ZIMRE Centre Cnr Hughes Street / Simon Mazorodze Road Masvingo
Mutare	ZIMRE Centre, 109 Herbert Chitepo Street Mutare
Victoria Falls	Town Office

Clients who wish to acquire motor vehicle registration books and number plates should approach the above ZIMRA offices and submit the requisite documents and payments. The public is also advised that the Zimbabwe National Road Administration (ZINARA), will have a temporary service counter at the ZIMRA Office based at Kurima House, George Silundika Avenue, between 3rd and 4th Street for vehicle licensing thereby bringing additional convenience to clients
ZIMRA on Twitter