The Market helps move resources between cities, trade with players and interact with farming villages. Its available functions depend on building requirements and world settings, so check the live interface before planning a large transfer.
Use trade to fix imbalances
Send surplus where it supports a planned upgrade, ship or research. Check capacity, travel time and destination storage first. Keep enough resources at home for queues and defence.
Village interactions differ
Trading with a village is not the same as sending resources to another player. Some worlds use requests and cooldowns. Read the farming village guide and economy guide. More tips are in the Grepolis hub.