Use this to convince vilagers your jesus.

Can you drag an item across the water with this spell?

Quote from Zimzky >>

Can you drag an item across the water with this spell?

 No; the description specifies that the spell is granting the ability to move across any liquid surface to willing creatures, not to objects.

You could have up to ten willing creatures carry an item across any liquid surface, if it is portable.

When you cross white water rapids, like the picture below, or worse movement of water. And this spell is used. Would this spell allow them to cross the water without any difficulty? as described in the spell it would become harmless solid ground. or would the 'ground' still be harmless but shaking en moving, and thus making it very difficult to cross?

I found this answer while wondering the same thing. "The surface you move across is treated 'as if it were harmless solid ground.' Since solid ground does not flow beneath you (except during precluded non-harmless events such as avalanches, earthquakes, mudslides, and sinkholes), neither is the river treated as flowing beneath you, so you are not carried along."

This question is a bit complicated to answer. The spell specifies that the creature must be voluntary, if a teammate is unconscious in the water and is sinking, can the spell be used on him to save him even if he has not said he is voluntary?

If you are submerged in lava would you take the damage or would it be negated?

Spell states you’d still take damage from the heat. 

Quote from SkyrimLover >>

If you are submerged in lava would you take the damage or would it be negated?

 Lava is too dense to sink in. You would involuntarily float on it even if you would want to get deeper. See "because science lava" on YouTube. 

If I charmed a underwater creature would he be considered willing? Cause that’s a good way to suffocate someone 

Quote from Hogan_Nantor >>

If I charmed a underwater creature would he be considered willing? Cause that’s a good way to suffocate someone 

 Maybe? Charmed means the creature sees you as a friend and you have advantage on charisma checks with it, but it’s not mind control. If your best friend told you to drown yourself, would you do it?

If this spell is cast on you, do you have the ability to go underwater, or are you stuck at the surface for the duration.  For example, enemy combatants are attacking from below the surface and then ducking below again.  Is there no way to follow them?

As the spell says, a creature is carried to the surface at 60 feet per round. So unless someone can go down at faster than 60 feet a round, they are stuck at the surface. 

Still waiting for this spell to get a better description of it’s effects under certain circumstances. Maybe it will in D&D 6e?

Only if they were targeted while underwater when cast and were willing. "If you target a creature submerged in a liquid,...” 

Quote from BardJan >>

When you cross white water rapids, like the picture below, or worse movement of water. And this spell is used. Would this spell allow them to cross the water without any difficulty? as described in the spell it would become harmless solid ground. or would the 'ground' still be harmless but shaking en moving, and thus making it very difficult to cross?

 I'd probably rule this difficult terrain since difficult terrain can still be harmless, just harder to move across.  To me this would be like trying to move across a talus/ scree field.

Use with speak with animal and you can have 10 fishes every day.

Water Walk (on ally) + Watery Sphere: Paladin walks on top of your floating ball of death and "fishes" for crits with advantage.

why is this not on the wizard list? must you punish us so for not being "devout" enough? *single tear

Wait, Snow??? That isn't a liquid.