Easy. Quit all applications. Copy your fonts in the ‘Fonts’ folder in the User’s ‘Library’. Enjoy.

Or follow these instructions from Apple.

Just follow the instructions from Microsoft.

Wow, you are dedicated. Unfortunately you can not install fonts on smartphones yourself yet. On a smartphone you are left to webfonts which are used on the websites you visit, or on fonts which come with the app you install. Sorry.

In case you’ve got a previous, older version of the same font installed already, you have to do the following before installing this new, updated version:

• Quit all applications (InDesign/Illustrator/Photoshop/etc)
• Deactivate and delete the old fonts
• Search for any files on your computer containing "AdobeFnt"
• Then delete those files which end with ".lst"*
• Install the new font
• Start up your application

*This is an Adobe cache thingie, which can cause trouble for Adobe programs when you have several versions of a font with the same name flying around. Delete these files first, if they exist.