ます or です?
When are ます and です used? Are they interchangeable?
「ます」is the formal verb ending. This means that after any verb, for example, 「答える」(こたえる, to answer). Replace the 「る」with 「ます」, and the verb becomes polite. The same goes for verbs ending in anything that isn't 「る」。Simply replace the /u/ with an /i/.
「です」on the other hand is used to politely say that something is something.
"That table is expensive." 「あのテーブルは高いですよ」
"The train station is far from here" 「電車駅はここから遠いです」
"Because the train station is far from my house, I have to wake up at 7am every morning" 「電車駅は私の家から遠いですので、毎朝午前７時に起きなくてはいいけません」
ます is used when someone or something DOES something, for example: the dog walks 犬は歩きます. です is used when something IS something, for example: the bed is blue ベットは青いです. Also, just as extra information, です and ますare used in the present and future tense. This ending makes the sentence you are saying more polite and formal.