The criminal pleaded guilty and submitted to the law.
Tips
usage
Two distinct senses share the same writing. 服 in 认罪服法 means 'to submit/yield' (as in 服从); in pharmacology 服 means 'to take (medicine)' (as in 服药). Context disambiguates.
mistakes
Don't confuse with 伏法 (fúfǎ, same pinyin) which specifically means 'to be executed under the law', a much narrower legal meaning.