how to add blog profile to pages and side bar

Hi,
I am running gridmarket multisite and am setting up an etsy style site. What I need to be able to do is to display a short site description, contact information and site information on the main store page and in the sidebar.
It would be ideal if it was like what is done on the etsy shop pages with an excerpt and then a modal window of full text and perhaps an avatar image. Here is an example , notice the description in the top of the page and the shop and owner information in the sidebar https://www.etsy.com/shop/theFiligree?ref=listing-shop-header-item-count

I was wondering if this should be done through the general settings, I was able to display the tag line and insert a custom field but not able to make it editable and limit its length. Also I have not been able to figure out how to customize the text box size of the general settings text boxes, they are very small.

This seems like a very basic necessity for a blog/site to have so I feel like I must be overlooking something. I also feel like this has been asked somewhere but I couldn't find an answer and after working on this for several days I admit defeat and need some help.

In addition in an unrelated issue on my user profile settings the biographical info box has gotten very large and is overlapping the password box, is there a way to shift it up or make it smaller.

Thanks again
Meriam