Unai Emery's Arsenal side lost to Chelsea in the Baku final after Eintracht were eliminated from the same side in penalties in the last four.
Standard Liege and Portoria Vitoria Guimaraes are also in Group F.
United, winners of the Europa League in 2017, will face Astana of Kazakhstan, as well as Partizan Belgrade and former finalists of AZ Alkmaar of the Netherlands in Group L.
Wolverhampton Wanderers, the third English team in the draw, will take the Turkish side Besiktas to Group K.
Meanwhile, the Celtic Scottish champions face Lazio and Rehn in Group E, as well as CFR Cluj, the Romanian side, from which they lost in the Champions League qualifications.
Scottish rivals Rangers will take on former European Cup winners P ortho and Feyenoord, as well as Young boys in Group G.
Meanwhile, Rangers have been ordered to close part of Ibrox for the second consecutive tie in the Europa League by UEFA for sectarian singing this season.
The Glasgow Giants secured a spot in the Europa League group stages with a dramatic 1
This is due to the original charge of "racist behavior", including sectarian singing, against St. Joseph of Gibraltar in Ibrox on July 18.
A second charge was brought against Rangers for chanting at Legia's far leg in Warsaw last week , which will again see 3,000 seats close for Ibrox supporters.
The club has announced that it will not accept tickets for its next visit to Europe in an attempt to prevent its closure.