You do not need to know which department, which form or which certificate. Describe the situation. We will tell you what it takes, what it costs and how long it is likely to run.
Visits to the office are by appointment. Most clients never need to come in person, which is rather the point.
For most tasks, no. Some government and legal processes require a formal authorisation executed and attested where you live. We tell you exactly what is needed at the quoting stage, before you commit to anything.