The sender and the name need not match
There is no rule that the person named on a record must be the one who posts it. The Legalisation Office works from the signature already on the sheet, so the sender is simply whoever addresses the envelope. That is why so many of these jobs are run by a relative at home while the person they concern is already living abroad.
What actually changes when it is not your paper
The plumbing around the route changes. Marked sheets go back to the address sent with them, so agree in advance whose address that is and who is holding the papers when they land. Where two people are involved, one of them should own the bundle from the first envelope to the last. Split custody is how pages go astray.
Money is the other thing to settle early. The British charge is £45 per document by post, or £40 per document on the next-day line where a registered business is running the job. Because it attaches to each paper, a helper looking after four sheets is paying four times, and that is a far easier conversation to have before the envelope goes.
The stage after the post
Togo has not joined the Hague Apostille Convention, so document legalisation for Togo carries on past the British slip. An apostille from United Kingdom to Togo is followed by a stamp from the consular staff acting for that country here, and whoever is running the job should plan to be free for that stage as well. It is not a step that finishes itself while you wait.
Habits that keep a borrowed job simple
Order fresh certified copies from Westminster Register Office rather than moving anybody's own certificate around the country. Keep each person's papers as a separate bundle. Write down which sheet belongs to whom, because a folder put together for three people is easy to hand back in the wrong order, and untangling it costs more than the copies did.
So what you need for an apostille for Togo is the same whoever sends it: a signed public version of each paper, the charge for each one, and a slot in the plan for the second office. The only extra when you act for someone else is agreeing in writing who does what, and where the finished bundle finally goes.