Currently, all of Outlook's accessibility features are shared with other apps, so they are listed in the Across App features page.
The web version does, however, allow for a good amount of personalization that can make it more accessible for you to use.
One example might be that you can create "Rules". These rules allow your emails to automatically be divided depending upon their content.
For example, I have a folder set up called Computers, and a group of rules set up so that anything with content referring to laptops, pcs, etc. goes straight to that folder so it does not get lost amongst general mail.
The web version of Outlook also allows you to customize how the general inbox displays.
To do this, go to settings, as above, and select Layout. On this page, you can experiment with settings to see what layout best suits you. An example of one the most effective options is "Hide reading pane", as the amount of information on the screen is reduced, and there are less distractions when trying to read emails.
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