In the Newsroom settings (in the menu under the gearwheel) you will find the following two text fields:

The Company description will be shown with the other company details on your newsroom pages. (To see e.g. your newsroom start page, click on your name in the upper right corner and choose Go to Newsroom.)

The Boilerplate will appear as your company’s signature on your press releases. By adding a boilerplate text in the Newsroom Settings, you create a default boilerplate, that will be automatically added to new press releases that, from now on, are created on the newsroom.

When creating a press release, you will be able to modify or replace the default boilerplate to make it fit a specific matter that you are writing about. To do so, click the Expand button in the Boilerplate section located at the bottom of the press release edit page.
In the case of an empty Boilerplate field in the press release, the boilerplate will be shown as defined in the Newsroom Settings (if applicable).

The boilerplate is only shown on press releases, but not on news, blogposts et al.

Your boilerplate is also shown in all emails that are sent out with the press release. Emails to your own contacts (excluding subscription emails to followers) will at the bottom of the email additionally include the Company description and an invitation to follow the newsroom.

It works fine to use the same text for both Company description and Boilerplate. But in the case that you want to diversify, you could e.g. in the Company description summarize what your business offers and what it does best. And in the Boilerplate focus more strongly on the most important facts and information that journalists need to know about your company.

Please also see:
Find the most basics settings for your Newsroom
Publish a press release, news or blog post
Press release, news or blog post – what’s the difference?
Where does the summary appear?