To redirect a WordPress page or post elsewhere, find the Theme SEO Settings box on the page or post editing screen. Enter the new URL in the Custom Redirect URL field.
To redirect pages from an old site with a different domain/URL) to the equivalent pages on your new WordPress site, go to Settings → 301 Redirects. Enter the old URL (minus the domain!) in the column on the left, and the new full URL in the column on the right.
If you have a list of redirects, activate the Simple 301 Redirects – Addon – Bulk CSV Uploader plugin to upload them all at once.