What software should used in finding a keyword inside the sentence?

Well I'm not sure if this is what you're asking or not, but if there was say a Word that you needed to find out of a page, or a sentence, then you would hit the *ctrl* button and your F key at the same time. You can try it out now, hit your control button at the same time as your F key and a little window comes up, type in the Word 'window'. Your computer should highlight the 2 times I used the Word. TO use this you must make sure you spelled the Word or phrase correctly and there is no extra punctuation in it. 'Finding' the Word youre is not the same as finding the Word you're.