How I can protect my grass yard green in winter?

Rake or blow all the leaves off the lawn.

Depending on where you live..most grass lawns go dormant in the winter.. and depending on the variety of grass you have... it will still go dormant in CA or AZ... want a green lawn in winter... use artificial turf.

You can't.It goes dormant in the winter

Depends on where you live. An awful lot of us have no green grass in the winter with the cold weather and going dormant. You should need to do anything unless it isn't too late to use the fall fertilizer in your area.

Some very nice grasses/ turf ( and expensive!) to include zoysia--do go dormant in the winter and fully recover next season. Its natural and expected.

Thank you

Fertilize it , and leave it be.

In order to have a green lawn in the winter you need to overseed with something like a winter rye. This will die out in the summer and your other grass will grow in.

Don't rake the leaves, nature made that for insulation to protect plants, trees, and the lawn.