All matters related to the provenance of a document are encoded in the Manuscript Description (<msDesc>) portion of the TEI header. In particular, they are placed within the <history> subsection (see further the general section on provenance).
Standard EpiDoc files include all relevant spatial, temporal, and circumstantial information about the initial discovery of a text-bearing object in a <provenance> tag with a type attribute bearing the value "found". Generally, there will only be one such element, unless separate fragments of the document were found in different locations. The information within each <provenance> element can take the form of one or more paragraphs of prose, or of a list (with appropriate TEI tags used as necessary). Sometimes circumstances and editorial approach will dictate that the contents of <provenance> element be largely prose; other times a more data-oriented encoding approach may be indicated. In either case, best practice is to tag place names, personal names and other information worthy of indexing, linking or querying appropriately (e.g., with <persName>, <placeName>, etc.).
Here is an example adapted from a milestone published in The Inscriptions of Roman Tripolitania:
And another adapted from an ostracon published in Papyri.info:
And a third from the Corpus of the Inscriptions of Cāmpa project, demonstrating the use of standard TEI date attributes to indicate the timing of the discovery:
It is often desirable, when objects are thought to have been found in situ, to indicate the relationship between place of finding and place of origin. Guidance and examples are provided in the section on Original location of the text-bearing object.