I have been trying to compute the least cost to reach 1800 urban centres (destinations) from 432 different villages (origins) using the DEM file as cost information.
I would appreciate it if anyone suggests me an elegant way to compute the least cost to reach the destinations.
I moved your post to ArcGIS Network Analyst Questions - Esri Community
this is the community for network questions
Are you trying to calculate the optimal path from villages to urban centres using a road network? If so, Network Analyst is the right tool for that job. However, you need a road network, not a DEM. Here is a tutorial to get you started: https://pro.arcgis.com/en/pro-app/latest/help/analysis/networks/od-cost-matrix-tutorial.htm
But since you mentioned a DEM, does that mean you actually want the least-cost path through the DEM, like a watershed analysis? If so, this is not the correct forum. You should ask your question in the Spatial Analyst forum: https://community.esri.com/t5/arcgis-spatial-analyst-questions/bd-p/arcgis-spatial-analyst-questions