I want to update my windows-10 computer but how to do it?

I don't want to pay $300 to have someone do it for me.

Any advise? Thanks for your effort.
Update: To Coaedhen: To answer your question. I want to run my computer normally. If you say Windows-10 will update itself how come I get the message I need to update it. Thanks for your response.
Update 2: What is search bar?
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