The Annapurna Base Camp trek is moderate to challenging. It is a trek, not a technical mountain climb. You do not need ropes or climbing skills in normal trail conditions.
The main challenge is the amount of uphill and downhill walking. Long stone stairways are common on the route. Many days also involve several hours of steady walking.
The trail ends at Annapurna Base Camp at 4,130 m. At that height, the thin air makes effort feel harder. Cold, rain, snow, and slippery steps can add difficulty. Some higher sections also have avalanche risk in poor conditions.
Most healthy trekkers can finish ABC with proper training and pacing. Train on hills and stairs before the trip. During the trek, use a steady pace and allow time to adjust to altitude.