Mishnayos Gittin Perek 1 Mishnah 4

Both bills of divorce and bills of manumission are the same with regard to the halakhot of delivering the document from Eretz Yisrael to a country overseas and with regard to bringing it from a country overseas to Eretz Yisrael, i.e., the agents for both types of documents must declare that it was written and signed in their presence, and their statement is accepted. And this is one of the ways in which the halakhot of bills of divorce are equal to the halakhot of bills of manumission.

אֶחָד גִּטֵּי נָשִׁים וְאֶחָד שִׁחְרוּרֵי עֲבָדִים, שָׁווּ לַמּוֹלִיךְ וְלַמֵּבִיא. וְזוֹ אַחַד מִן הַדְּרָכִים שֶׁשָּׁווּ גִטֵּי נָשִׁים לְשִׁחְרוּרֵי עֲבָדִים: