Go to settings > permalinks in your admin panel. There I chose the format of my permalinks. I advise to choose one of the suggested, it is easier.
The name of the single post in my blog include the name of the author before it. If you leave the “category base” and “tag base” boxes empty, then WordPress will display default settings – “topics” and “tags”. On my blog I have www.mydomain/key-words/video or /categories/my-life/. It is reasonable to change them for something shorter.
I clicked “Save changes” in the bottom, and the WordPress warned me that my .htaccess file is not writable and either WordPress or I should write new rules in .htaccess file. There was the text in the box which I had to copy and paste in my .htaccess file in the WordPress directory in my hosting account.
I pasted the text and went to the site. If you want to use other method (change permissions for the .htaccess file so that WordPress could write in it), don’t forget to return the permissions for it to safer numbers (644, for example) after the changes are made.
I noticed that permalinks for my posts became readable which was very convenient for me and for my readers.