1. Take sogou input method as an example, and right-click input method.
2. In the pop-up list, select "soft keyboard"-"2 Greek letters".
3. In the dialog box, click the key of the letter B with the mouse and insert the symbol β.
4. You can insert other Greek letters at the same time, just click the mouse.
α、β、γ、δ、ε、ζ、η、θ、ι。
κ、λ、μ、ν、ξ、ο、π、ρ。
σ、τ、υ、φ、χ、ψ、ω。