1. My app provides cloud package service on multiple platform for that I can use IAP. Is it fine?
You may use IAP unless you the main use of the 'cloud package service' is to be used outside of your app:
- 3.1.5(a) Goods and Services Outside of the App: If your app enables people to purchase goods or services that will be consumed outside of the app, you must use purchase methods other than in-app purchase to collect those payments, such as Apple Pay or traditional credit card entry.
2. My app also provide online consultation with my user and there is a charge for consultation on hour basis. Should I use IAP?
If the consultation is done outside the app you may not use IAP (see 3.1.5(a) above). If the consultation is done within the app then 3.1.5(a), as written, does not prevent you from using IAP. It seems to be your choice whether or not to use IAP. An earlier version of 3.1.5(a) did not include the phrase "that will be consumed outside the app" - it would have barred your use of IAP.
3. My app has a section of packages of multiple types of dektop tools, that is usable on desktop browser. So as this is also a digital goods but not consumable from IOS App.Should I use IAP?
I assume this is something that is used only outside your app. If it is a "service" then 3.1.5(a) says you may not use IAP. I think it is a "service" and, as such, IAP may not be appropriate.
If I have it right, you're attempting to sell packaged cloud services that work on both mobile and desktop platforms, that includes live consultation, all of which can be both consumed and purchased inside and outside of your iOS app.
ASRG 3.1.3(b) Multiplatform Services says this about that... "provided those items are also available as in-app purchases within the app", and my opinion, since App Review doesn't participate here, is 3.1.3(b) is the main factor in your example, just be sure you explain to review that your app's focus is multi-platform via that app's meta data review notes.
That said, you may want to ping support via the contact us link just to get their feedback. It would be interesting to learn how this works out once app review takes a look, so if you have time, pls. do a followup here, thanks.