I think this may be her marriage record, although it gives her middle name as Cecilia rather than Catharina:
"South Africa, Transvaal, Civil Marriages, 1870-1930," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:QG52-B75J : 27 September 2019), Petrus Johannes Le Roux and Anna Cecilia Dreyer Brits, Heidelberg, Heidelberg, Transvaal, South Africa; citing Marriage, Heidelberg, Heidelberg, Transvaal, South Africa, NARS "Civil registration (marriages - coloureds), Transvaal and Swaziland, 1898-1927." The National Archives and Records Service of South Africa, Pretoria.
The image shows her birthplace, although I am not familiar with South African place names so I'm not certain what it says - maybe Potchefstroom?
