In Nokia, I did it by typing *71003584012345678
where 71
for the unanswered calls, 00358
for the Finnish country code and the phonenumber 4012345678
.
I know there are many applications for the task but I do not want to use them.
I heard that some Nokia Android phones and Sony phones have a builtin feature for the call forwarding in their phones.
However, I cannot find such a feature in my Oneplus.
Phone: Oneplus 3T
OS: Android 7.1.1