I can only write a message, but to do that would I have to upgrade my account?
I do have messages with a free account, so no, you don't have to upgrade.
I would like to be connected to a friend of mine on LinkedIn, but I am not able to do that because I do not find the possibility.
How is it possible? I think about limitations setting by that users, but I do not know any of those settings.
There are settings regarding how to manage "invitations" (sorry if it's not the word, i'm roughly translating from Spanish)
- Anyone on LinkedIn
- Just people that knows your email address or appears in your list of imported contacts
- Just people that appears in your list of imported contacts
If it's a friend of yours, the best way to handle this would be to ask him (by regular email) to contact you (by linkedIn) provided that you have the setting "anyone on linkedIn"