Need to know do I out yellow wire with the black wire o. The new fixture? Old is white yellow out of wall New fixture is black and white.

Unless you are located in the UK or EU the wires out of the wall should be black and white. Don't know how a black wire could turn yellow unless it is paint.

Assuming that there is only two wires coming out of the wall at fixture, go to switch and remove it. At the switch you should find the white to the fixture connected to one or more whites. There should be two blacks attached to switch. One of those blacks will be the other end of the yellow.

If all of that is true connect white to white and black to yellow.