Often, agencies will send their sales team to pitch you on hiring them and, more often than not, they are not the people that will actually build your website. If a salesperson offers to let you follow up with one of their developers, take them up on the offer and ask this question again. The web professional or agency should be capable of telling you what version of HTML they use for building websites. Noting that code (or at least portions of it) will be written by hand, rather than auto-generated by software, is often a positive sign; but many good web professionals employ software such as Adobe’s Dreamweaver or Microsoft’s Expression Studio to help them build simpler pages more quickly.