Hello Jennifer

This is not possible with X5. Unless your client also have a version of X5. And then you will have the synchrobizibg problem.

Try to find some free blog software.

Or - if you use one.com as provider, then they have an excellent blog feature where you can create users and give them access to create posts. You can also give access to who should be allowed to comment.

You could have more users that were allowed to create new posts, and then public were allowed to comment.

The X5 software is only for a person that makes his own site, and then have a blog where only he can create new posts but all could comment.

My suggestion - find some good free blog software and integrate this software with X5. This can be done either via links or via iframes. Links will be the best. This will be much the same as the way X5 functions. 

Here : https://helpcenter.websitex5.com/ru/post/205643

you can see that you are not alone with this problem. Even if the PRO version should be for proffessionels, then it is not regarding shop and blog.

You cannot create a webshop or a blog for a client.

As you have guessed, it will require that the client can maintain the webshop ( products + prices ) and/or the blog from an administration panel.