ありがとうございます

Meanings

polite (teineigo)usually written using kana alone

Polite expression of gratitude, more formal than ありがとう. Used in business, with strangers, or when showing respect.

どうもありがとうございます
どうもありがとうございます adds どうも to intensify the gratitude expressed by ありがとうございます, making it sound even more polite or heartfelt.
誠まことにありがとうございます
ありがとうございます is the basic polite 'thank you', while 誠にありがとうございます adds 誠に for a more formal, emphatic tone used in business and service settings.
ありがとうございました
ありがとうございます is the non-past polite form used for present or ongoing gratitude, while 有難うございました is used after the fact for something already done.
おかげさまでN4
ありがとうございます is a direct thank-you, while おかげさまで indirectly credits others' support while reporting that things are going well.

ありがとうplainN4
ありがとうございます is the polite form used with strangers or in formal settings, while ありがとう is the casual form used with friends and family.
サンキューplainN1
ありがとうございます is the polite form used with strangers or superiors, while サンキュー is a slangy casual form only for close friends.
どうもありがとうplain
ありがとうございます is the standard polite form used in formal or business settings, while どうも有難う is a warmer, everyday emphatic thanks.
ありがとplain
ありがとうございます is the polite/formal counterpart used with strangers or superiors, while ありがと is casual slang for close relations.

すみませんN4
すみません can also convey thanks (for trouble taken on one's behalf), but it primarily means 'excuse me' or 'I'm sorry', unlike ありがとうございます which is purely an expression of gratitude.

有難ありがとうございます
Kanji spelling using 有難う; rarely used in modern writing.
有あり難がとうございます
Kanji spelling with okurigana 有り難う; very rare.
有難ありがとう御座ございます
Full kanji spelling including 御座います; extremely rare and formal-looking.
ありがとう御ご座ざいます
Mixed kana-kanji spelling; very rare.
有あり難がとう御座ございます
Full kanji spelling with okurigana; extremely rare.

The polite expression combines ありがとう, the euphonic adverbial form of 有り難い “rare; welcome; appreciated,” with ございます.