Thank you for your responses !
@jj2007: I am a beginner in assembler under Windows after using a lot MASM under DOS in the early 90s. Being studying the structures DLGTEMPLATE and DLGITEMTEMPLATE, I discovered that the strings had to be specified in Unicode format. So I wondered about the possibility of directly declare these strings in Unicode. GoAsm (and probably NASM too) can, but not MASM 6.15 which is, if I'm not wrong, the only version to run autonomously (beyond that, Visual C ++ is required). So I do not have a specific project. Unfortunately, I don't have a PC for the moment and I will study your precious suggestions in a little more than 2 weeks.
@newrobert: thank you very much for your info. I know, indeed, the function MultiByteToWide that allows to perform this conversion but I'm rather interested in a direct declaration of the string in Unicode'