To sign from a PC you can install the free software IG DESK or to sign from a smartphone the free IG SMART software.
In both cases you have to download the IG YOU App on your tablet or mobile phone to authorize the signature.
N.B. If you have a Huawei Android smartphone, you can download IG YOU from the AppGallery.
IG YOU is NOT available for Huawei smartphones with HarmonyOS.
Minimum supported versions: Android: 5.0 Lollipop (API level 21) and iOS: 10.0.