He designed and printed postage stamps.
"Shortly after the Arab Revolution [i.e. when the Arabs declared their independence] we found that its success was being denied or blanketed by Enemy Press .., and we decided that the best proof that it had taken place would be provided by an issue of Hajaz postage stamps, which would carry the Arab propaganda, self-paying and incontrovertible, to the four corners of the earth. Sir Harry MacMahon [1862-1949], High Commissioner Egypt [1914-1916] was quick to approve, and the Foreign Office approved him. I had corresponded with King Hussein on the project, and he sent me by return of mail a design purporting to typify Islamic architecture, but to the layman indistinguishable from the Eddystone Lighthouse. I felt that this would never do, and wandered around with Lawrence round the Arab Museum in Cairo collecting suitable motifs in order that the design in wording, spirit and ornament, might be as far as possible representative and reminiscent of a purely Arab source of inspiration. Pictures and views were avoided, for these never formed part of Arab decoration, and are foreign to its art; so also was European lettering.
"It was quickly apparent that Lawrence already possessed or had immediately assimilated a complete working technique of philatelic and three-color reproduction, so that he was able to supervise the issue from start to finish."
The primary philatelic references to Lawrence and these stamps are:
BEECH, David R. Hejaz: The First Postage Stamps of 1916 and T.E. Lawrence: Additional Information (The London Philatelist, vol. 116, pp. 38-40, March 2007.