There are two simple ways to print test symbols on Apple mobile phones:

1, you can add a Greek keyboard by setting-"Universal Keyboard-",which is Latin, and you can find the beta symbol in it.

2, you can download Baidu input method, which has symbols.

When writing documents on mobile phones, sometimes we need to use special symbols. θ (tangent), α (α) and β (β) are commonly used to represent the number of angles in trigonometric functions.