Important threshold to care about: TWD 500,000. If your inbound transfers are above this amount, you basically can’t escape a visit to the branch to sign/stamp a form (bring ID).
Below that, it depends on your bank. Your relationship with your bank is important in Taiwan. Aim to get to know the people who are processing your transactions (most likely staff at the branch where you open the account), and treat them well they can help tailor service to you.
It took me about 12 months to ‘train’ my bank, but now they no longer call and instead just accept the funds and email me a PDF of the completed paperwork (and post a hardcopy for my accountant). They call only when the amount is over TWD500,000 and I need to visit the branch, or something has gone horribly wrong.
It is true that inward international transfers need to be tagged with a purpose. It’s more about putting a code in a box to categorise them than explaining their legitimacy.
The document you’ll need is this one:
Page 79 - Classification and Description of Inward Remittance
(if you are sending funds overseas, the outward version is a few pages up)
Look up the appropriate code for your transaction type.
So, for example, if you are able to tell your new friends at the bank that every transaction you get is “19D” (Professional and Technical Service receipts), they’ll be able to look up the Chinese version of the same document and be satisfied with that.
One very critical thing:
In my experience, Taiwanese banks care a great deal that the account name on your account matches the beneficiary name of the transfer. This is to the extent where even line-wrapping can throw them off.
If your (English) company name is longer than 35 characters, chatting with your bank about this first could help you. You may have to add instructions like “Add ‘Full Beneficiary Name: My Company With Long Name Taiwan Branch’ in the description field” to your invoices.