Sending money to someone else, another bank, or overseas
When to use
Sending money to others, Sending money overseas, Transfer outside bank
The nuance
Used mainly when sending money outside your bank or to others, including overseas remittances.
송금 (song-geum, songgeum) · 이체 (i-che, iche)
송금 generally refers to sending money to others or outside your bank, while 이체 is mainly used for transferring money within the same bank or between your own accounts.

One lane per word — no nested boxes, just the gist.
Sending money to someone else, another bank, or overseas
When to use
Sending money to others, Sending money overseas, Transfer outside bank
The nuance
Used mainly when sending money outside your bank or to others, including overseas remittances.
Transferring money between accounts within the same bank or between your own accounts
When to use
Transfer between own accounts, Transfer within same bank, Internal bank money movement
The nuance
Used for money movement within the same bank or between your own accounts, generally handled internally by the bank system.
나는 친구에게 송금했다.
na-neun chin-gu-e-ge song-geum-haess-da., na neun chin gu e ge song geum haess da.
Sending money to another person (friend), so '송금' is correct.
나는 내 다른 은행 계좌로 이체했다.
na-neun nae da-reun eun-haeng gye-jwa-ro i-che-haess-da., na neun nae da reun eun haeng gye jwa ro i che haess da.
Even if different banks, transferring between own accounts is '이체'.
나는 회사에 이체했다.
na-neun hoe-sa-e i-che-haess-da., na neun hoe sa e i che haess da.
Sending money to a company requires '송금'; '이체' is mainly for own account transfers.
은행에서 해외로 이체를 했다.
eun-haeng-e-seo hae-oe-ro i-che-reul haess-da., eun haeng e seo hae oe ro i che reul haess da.
Overseas transfers are '송금'; '이체' is limited to domestic bank internal transfers.
내 통장 안에서 이체를 했다.
nae tong-jang an-e-seo i-che-reul haess-da., nae tong jang an e seo i che reul haess da.
Moving money between own accounts fits '이체'.
친구에게 이체했다.
chin-gu-e-ge i-che-haess-da., chin gu e ge i che haess da.
Friend is another person, so '송금' should be used.
은행 ATM에서 송금했다.
eun-haeng atme-seo song-geum-haess-da., eun haeng atme seo song geum haess da.
Sending money to others or other banks via ATM is '송금'.
내 다른 계좌로 송금했다.
nae da-reun gye-jwa-ro song-geum-haess-da., nae da reun gye jwa ro song geum haess da.
Transferring between own accounts is '이체'; '송금' is for others.
Which word is most appropriate when sending money to a friend?
Which word is appropriate for transferring money between your own accounts?
Which word is used when sending money overseas?
Which word is appropriate when sending money to another person's account within the same bank?