What are the default properties that page or Assets get when we create?

There are not any set of properties defined that will come by default on creation. It depends on the setup you have of AEM. Properties like title will always be there but there could be other properties that would come by default based on the integrations you have with AEM. Even properties could vary based on AEM version as well.

For example if you are using dynamic media integration then your assets will have bunch of properties related to scene7. Also few properties varies based on the type of Asset you are uploading. 

Let's talk about page first -

While creating a page are you getting below create page wizard? If yes

Please notice here Title is the mandatory field [it marks with asterisk]. To  create a page I have to add title and if I don't use any other properties [don't define any other properties], then cq:lastModified, cq:lastModifiedBy, cq:template, jcr:title, sling:resourceType, jcr:primaryType, jcr:created and jcr:createdBy will be stored/created as shown below -

If you define more properties during page creation then more properties get created/stored in CRXDE.

Next based on author's action we will be seeing more properties.

For an asset you will seeing more properties as shown below -

You can easily test all these at your end also.