Some of these initials refer to training that the practitioner had before studying homeopathy. These include:
MD or DO medical doctor
ND naturopath
DC chiropractor
L Ac. accupuncturist
etc. None of these credentials indicate a persons ability to practice homeopathy.

The credentials that do count are the ones from homeopathic certification groups, who examine applicants for their education and skills in homeopathy. These include the following credentials
RSHom (NA) registered society of homeopaths north america
DHANP diplomate homeopathic association of naturopathic physicians
DHt diplomate of Homeotheraputics
CCH certified in classical homeopathy
All of these are good indicators of a quality homeopath.

Other initials may come from a school, or from some other certification programs which are not as good, in my opinion, as the ones listed above.