Trekking Packing List

T-shirts (Lightweight & Instant-drying)
Trekking Pants
Long-sleeved Shirt
Fleece Jacket
Rain Jacket
Down Jacket
Extra socks
Shoes (lightweight and comfortable)
Water Purifier Bottle
Sleeping Bags 
Cash (No ATMs are available in remote areas)
Water bottle minimum of 1 Litre (Refilling in taps or buying new ones in tea houses)
Backpack (30-35 litre)
Sunscreen cream
Insect repellent (Especially on summer season)
Hat made up of Woolen or Cotton
All necessary documents (Before the trip starts)

Other Gear

Hand Sanitizer
Toilet Paper (You can purchase on the way as well)
Trekking Poles
Small First-Aid Kit (Antiseptic cream, bandage, cottons)
Personal Medicine (If you take any)
Instant Drying Towel
Soap and Shampoos
Flashlight (For emergency purposes)
Dust Mask (Paper or cloth)
Cameras with extra sets of batteries
Power Bank (so you can charge along the way)
Binoculars (as per your wish)

You can purchase or rent these items in Nepal
You can find these items in city areas like Kathmandu and Pokhara, not in rural areas.