1) First Select whole Excel Sheet by Ctrl+A After that
2) Right Click on excel sheet you will find Format Cells Option that screen look like this
3) Click on Format Cells option you will find one window like this
4) In that window you will find tab menu in that you should click on Protection tab you will find two options
Locked and Hidden. Here we should uncheck the Locked option and click OK button
5) Now click on particular cell you want to protect, right click on that go to Format Cells Option -> Protection and click on that check the locked option
6) After Completion of that in Home tab right side you will find Format Option like this find the options those are marked with red circle
7) Click on Format Option you will find Protect Sheet Click on that option one small window will open in that check select locked cells and select unlocked cells and if you want lock the cells with password enter password in the textbox .
