Don't iphones automatically save a lot of things to the cloud? Not sure about texts and WhatsApp, but it's something to look into. Outside of that, you may have to go to a phone repair or data recovery place. 

Thanks Jim. Yes I went to repair shop to check what the problem is. There is liquid in it. They say there's possibility to recover data . An specialist. in France or Zürich but because of pandemic (2020) .  It didn't happen.

Now I try search on google but a bit scary to download those stuff, maybe virus. 
I maybe have a luck here and bit cheaper. 

Ah I see. I would definitely be cautious about downloading anything for data recovery - that seems ripe for a scam/virus. 

Not really my subject.. but..

?Ring the apple helpline and see if they can help, or have any advice...  call is usually free..

0800 84 51 23

Otherwise there's an apple store in Annemasse (internet search for address etc), that might be worth asking  for addresses of Apple affiliated shops /repairers in the area

Water corrodes the electronics. The longer you keep the phone without drying, the more chances there are of causing irreparable damage. Water also conducts electricity, so the risk of causing a damaging short circuits are very high unless you immediately remove the battery, ... do not try to power it back on until perfectly dry ... one way to make sure it dries all internal parts, put it in a tupperware with rice for a few days ... If it's salt water, things are much worse, corrosion will work much faster because of the salt. In that case I managed to save my phone by sinking it in pure alcohol ... shake it well so that the alcohol reaches everywhere, it helps to disolve the salt and get it out ... Then, after a few hours in the alcohol, let it dry in the rice for a few days before trying to switch it back on.

Anyway, your case is very special because it's been so long since the water damage. But the advice above is general ... and the key is to react quickly!

Thank you Ajimenez.  It was not salt water. It was lake water . In case it happens to my new iPhone. I will do your tips. 
the cost of recovering data is around 800 chf according to repair shop and not 100% guarantee . in France is cheaper . 

I don't trust data recovery, they never work.

I got my iphone in water and I recovered myself, always best option.

Ask a friend who you can trust.