There have been Accessibility options to change the appearance of your iPhone apps for some time now. For instance you can change the font size, use bold text, change contrast and so on. Any changes you make, however, are system wide and will affect all of your apps. Not so in iOS 15 - now you can change the appearance of apps on a per-app basis. Here's how to do it on iPhone:
Just about every iOS update improves the Notes app with additions such as note sharing, password protection, tables, folders and more, making it a much more useful app. iOS 15 continues the evolution with the addition of Tags (think hashtags), which makes it a lot easier to find the note you're looking for. Now you can categorize your notes simply by adding a hashtag (or multiple hashtags) to them, then you can search by hashtag. Here's how to use hashtags in the Notes app on iPhone:
Ambient noise, white noise, dark noise; whatever you want to call it, the App Store abounds with apps dedicated to playing background noise to help you focus, find calm, fall asleep, tap into your subconscious and so on. Apple has taken note of the general enthusiasm regarding such apps and has added its own background noise feature in iOS 15 - Background Sounds. It isn't a stand alone app, rather it is an Accessibility feature that you can use to drown out distracting noise in your environment, help you meditate, help you sleep and so on.
For many of us it is not unusual to have many tens if not hundreds of tabs open in Safari. Between opening new tabs with every link you tap on in an email or other message and leaving tabs open to come back to later (instead of bookmarking them or adding them to your reading list), they can quickly add up. iOS 15 introduces a powerful new way of organizing them - Tab Groups. With Tab Groups you can organize your tabs into categories so you can quickly locate the one you're looking for, rather than searching through a hundred tabs.
One of the benefits of having a YouTube premium membership, along with picture-in-picture (not available everywhere at the time of this writing) and access to YouTube Music, is the ability to play YouTube in the background. This lets you listen to your favorite YouTube channels while using other apps on your iPhone or iPad, or listening with the screen off. If you have a premium account, here's how to listen to YouTube in the background: