Partita was originally the name for a single instrumental piece of music (16th and 17th centuries), but Johann Kuhnau ( Thomaskantor - 1722, followed by Bach ) and later German composers (notably Johann Sebastian Bach) used it for collections of musical pieces, as a synonym for suite.
Johann Sebastian Bach wrote two sets of Partitas for different instruments. Those for solo keyboard the composer published as his Opus 1 (known as the Klavierübung I). One additional suite in B minor, the Overture in the French Style (often simply called French Overture) is sometimes also considered a Partita. Bach's Partitas are very rarely called the "German Suites", in analogy with the "national" naming of the English and French Suites. See Partitas for keyboard (825–830) and choral partitas for organ.
Bach also wrote three partitas for solo violin in 1720 which he paired with sonatas. See Sonatas and partitas for solo violin
Johann Kuhnau: a choral partita from 'Biblische Historien',
Here it is called 'Sonata 4' ( a programatic title is added ). The tune or cantus firmus is the famous choral 'O Haupt voll Blut und Wunden'
'Der todtkrancke und wieder gesunde Hiskias', 6,56MB (help·info)