Wolff, who raced as Susie Stoddart before she married Williams's shareholder Toto Wolff, will contest her seventh season in the DTM this year.
She will work with Williams's simulator before she takes to the track in a test in the coming months, according to the team.
"Susie is a talented, successful and highly professional racing driver who competes in one of the world's most fiercely-contested racing series," said team boss Frank Williams.
"Susie will join Williams as a development driver, in which capacity she will assist us with the development of our simulator and other technical challenges. Susie will also undertake some aerodynamic testing of the FW34 and a full track test in the coming months.
Susie will also attend a number of races with us. I should add that, as Susie is married to Toto Wolff, a director of Williams, her appointment was carefully considered and then approved by the board, with Toto recusing himself from the process."
Wolff added: "Formula 1 is the ultimate challenge for any racing driver and it offers me the chance both to apply and to improve the skills I have developed racing in DTM. In return I shall be offering some of my own technical insight and experience - coming from a different discipline – and helping the team engage with its partners.
"I hope also to demonstrate that women can play a role at the highest levels of motorsport and I shall be working closely with the team on its social responsibility programme in the areas of education and road safety."
Formula 1 supremo Bernie Ecclestone also welcomed the announcement.
"If Susie is as quick in a car as she looks good out of a car then she will be a massive asset to any team and on top of that she is very intelligent. I am really looking forward to having her in Formula 1."
