Most German verbs are regular: the stem stays the same, only the ending changes to match the subject. Remove -en from the infinitive to find the stem, then add the right ending.
The stem "mach" never changes — only the ending does.
| Person | machen (to do/make) |
|---|---|
| ich | mache |
| du | machst |
| er/sie/es | macht |
| wir | machen |
| ihr | macht |
| sie/Sie | machen |
What ending goes with "du" for regular verbs?