‘See off’ implies going with someone physically, not just saying goodbye from afar. I went to his house to see him off on his journey.
Pro Tip 2/3
Not a Farewell Party
‘See off’ is more personal and less formal than a farewell party; it's usually a smaller, intimate group. The family gathered to see off their daughter as she left for college.
Pro Tip 3/3
Emotional Moment
Seeing someone off can be emotional; it often signifies an important change or long separation. Tears were shed as they saw their friend off to the army.