How I Concise the Blog Text Area?

Hi,

I know I ask lot's of question because I am beginner in blogging so, please don't mind. Here is my query is How I set up short the text area? Not so much wide spaces.

I prefer this size of space which I mentioned the attached file.

Regards,
Nitai Roy
https://www.clippingpathoutsource.com/blog/why-product-photo-retouching-is-important-in-the-digital-era