This is similar to Matthew, chapter 26:18, and Luke, chapter 22:11. Mark indicated that Jesus told his 2 unnamed disciples what to say to the proprietor or the owner of the house, as he entered it (καὶ ὅπου ἐὰν εἰσέλθῃ εἴπατε τῷ οἰκοδεσπότῃ). They were to say that the teacher asked him where his guest room was (ὅτι Ὁ Διδάσκαλος λέγει Ποῦ ἐστιν τὸ κατάλυμά μου). Jesus wanted to eat the Passover at this house with his disciples (ὅπου τὸ πάσχα μετὰ τῶν μαθητῶν μου φάγω). This Passover was the remembrance of the Israelites fleeing Egypt by eating special foods. There is no indication of whose house this was or who the owner of the house was. Certainly, it was someone who knew Jesus.
This is similar to Mark, chapter 14:13-14, and Luke, chapter 22:10-12, who both mention that the man has a jar of water, something not mentioned here. Jesus said that they were to go into the city of Jerusalem (ὁ δὲ εἶπεν Ὑπάγετε εἰς τὴν πόλιν) to a certain unnamed man (πρὸς τὸν δεῖνα). The other 2 gospel writers said that this man was going to be carrying a jar of water. They were to say to him (καὶ εἴπατε αὐτῷ) that the teacher said that his time was near (Ὁ Διδάσκαλος λέγει Ὁ καιρός μου ἐγγύς ἐστιν). Jesus wanted to keep the Passover (πρὸς σὲ ποιῶ τὸ πάσχα) at his house with his disciples (μετὰ τῶν μαθητῶν μου). There was no explicit mention of a guest room in this house as in the other 2 synoptic gospels. This Passover was the remembrance of the Israelites fleeing Egypt by eating special foods.