Yes, it is common for locals to invite foreign visitors for tea, and sometimes meals, as a gesture of hospitality.
Tea as a welcome
Hospitality is an important cultural value in Pakistan. Offering tea is a simple and traditional way to welcome guests or start a conversation.
Urban and rural differences
In cities and tourist regions, invitations may be casual and brief. In smaller towns, they can feel more personal and sincere.
How to respond
You are free to accept or decline politely. A respectful response is appreciated either way.