How to use alternate characters in Apple Pages, Microsoft Word

[EddiOS42]

I downloaded the Inter Variable typeface and installed it into my Font Book app. I would like to use the alternate open numbers and slashed 0. How can I do so on those applications?

[kenmcd]

AFAIK the only font feature Apple Pages supports is ligatures.
And probably only Standard Ligatures.

Word does support Stylistic Sets so the open numbers in ss01 would be supported.
Word does not support the Slashed Zero zero feature.

You could "freeze" your desired features into the font using Font Freeze or OpenType Feature Freezer.

Font Freeze
repo: https://github.com/MuTsunTsai/fontfreeze
online tool: https://mutsuntsai.github.io/fontfreeze/

OpenType Feature Freezer
https://github.com/twardoch/fonttools-opentype-feature-freezer

If you freeze the features it will then work even in Pages.

Note:
LibreOffice supports all of the Inter OpenType features.
Affinity (now free) supports all of the Inter OpenType features.
May be better to learn one of those instead.

[EddiOS42]

It successfully modified the file, but the results don't align. Tried deleting all the files, redownloading, and modifying again.

[kenmcd]

The INFO shows no features selected (features='',) and all the desired features in the language option ( lang='cv01,cv03,...etc.').
So it appears that something is off in the input.

Not sure if OTFeatureFreezer works with variable fonts.
Font Freezer does.