Yoast SEO -
Install and activate the Yoast SEO plugin.
Go to/click Pages.
Select/click the page you want to update.
E.g. Home
Under Yoast SEO section (normally at the bottom):
Expand the Snippet Preview by clicking it.
Click Edit snippet.
Now you can edit the meta title and description that you want for this page.
Fill up the following fields:
SEO title
Slug
Meta description
For the Home page the format should be:
SEO title: Site title - Tagline (See screenshot below)
Slug: home-page
Meta description: <meta_description>
Note: You can leave this one as blank.
Click Update to save your changes.
Go to/click Pages/Posts/Listings.
Select/click the page/post you want to exclude.
E.g. Payment Fail
Under Yoast SEO section (normally at the bottom):
Click the Settings/Gear (Advanced) icon.
Under Advanced tab:
Set Allow search engines to show this Page in search results? to No.
Set Should search engines follow links on this Page? to No if necessary.
Click Update to save your changes.