After burying Sarah, Abraham sent his servant, Eliezer, to his brother’s household in Aram to select a suitable wife for Isaac.
G‑d’s Estranged Wives
כִּי אֶל אַרְצִי וְאֶל מוֹלַדְתִּי תֵּלֵךְ וְלָקַחְתָּ אִשָּׁה לִבְנִי לְיִצְחָק:
(בראשית כד:ד)
[Abraham told Eliezer,] “You must go to my land, to my family, and take a wife for my son, Isaac.”
Genesis 24:4
The prophets often describe the relationship between G‑d and the Jewish people as that of husband and wife. In this sense, we are all entrusted with a mission comparable to the one that Abraham gave Eliezer – to go out and find those souls that have drifted away and bring them back to G‑d, their “husband.”1

If the Jews believe in free will, why have anyone chosen for a partner by the parent? If it was simply the custom in those days, why do we not continue it?
Hello anonymous,
The reasoning for parents being involved was to remove the possibility of bad judgement by the child, and the fact that many marriages were financially based, not romantically.
Over time, with the age of marriage going up, thus allowing the children to mature and decide for themselves rationally, and with the financial aspect of marriage taking a back seat, arranged marriages were canceled.
It was a custom, but not a halachic custom, just something that people did.