Which steps should I follow after uninstalling the Accessibility app?

No further action is required. When you uninstall, the widget stops showing on your storefront and your widget settings and app access are cleared, so if you reinstall later the app starts with default settings. If you had turned on the Accessibility Toolkit app embed in your theme, you can switch it off under Online Store > Themes > Customize > App embeds. You can reinstall the app at any time from the App Store.

Get accessibility app for Shopify from here Accessibility Toolkit