To express going somewhere to fetch or retrieve something (like going for groceries or sending for a doctor), Russian uses the preposition за followed by the Instrumental case.
Sending for Help
If an errand is urgent, you might need to send someone else to do the retrieving. Use the verb послать (to send) alongside за + Instrumental. Remember that for masculine and neuter nouns, use the Instrumental endings -ом / -ем, and for feminine nouns ending in -а/-я, use -ой / -ей.
| We urgently need to send for a doctor. | Нам нужно срочно послать за врачом. |
| In my opinion, they sent Anna for the first aid kit. | По-моему, они послали Анну за аптечкой. |
Running Errands
This grammar is very common with verbs of motion for round-trip errands. The verb съездить means "to drive (somewhere) and return", so combining it with за expresses driving somewhere specifically to pick something up.
| I must drive to the pharmacy for a new first aid kit. | Я должен съездить в аптеку за новой аптечкой. |
When talking about going shopping, Russians literally say they are going "for purchases" (за покупками, using the plural Instrumental ending -ами / -ями).
| On the weekend we will drive to the shopping center for purchases. | В выходные мы съездим за покупками в торговый центр. |
Documents and Spare Parts
You will also use за + Instrumental in administrative contexts, such as dropping by an office to pick up a permit (разрешение).
| In the morning the director dropped by the office for the permit. | Утром директор заехал в офис за разрешением. |
When fetching multiple items connected by и (and), you only need за once, but every item that follows takes the Instrumental case. Note that feminine nouns ending in a soft sign (like запчасть — spare part) take the unique ending -ью (запчастью).
| The mechanic returned to the garage for the duplicate key and the spare part. | Механик вернулся в гараж за дубликатом ключа и запчастью. |