There are diverse reasons why one entity might want or need to use the real property of another, so there have evolved differing ways that easements can be created.
1. Easements can be created by written agreement of the parties.Suppose two adjoining parcel owners have a common or "shared" well for water supply. An agreement might be created setting out the ways that costs to maintain the well might be shared and also setting up an easement for the owner of the property on which the well is not located to gain access for permitted activities regarding the well.
2. A deed conveying property can create an easement.Suppose an owner of a 40 acre land parcel wanted to sell the back 20 acres. In order for the new owner of the back parcel to access the public road, an easement would be created in the deed specifying which portion of the front 40 acres were to be used for this access and even possibly drawing out a driveway access on a survey.
3. Easement by Necessity is usually by court order.Closely related to the deed example above, suppose that a piece of property exists with no access to a public roadway due to surrounding properties owned by others. However this situation was created in the first place, most states recognize that a property owner has a right to be able to enter and exit (right to ingress and egress) their property.
In this case, a court could issue an order creating an easement by necessity across one of the neighboring properties.
4. Easement by condemnation is used for the public good.Though the owner of a property might have strong disagreement with the "public good" statement, a government might condemn a property or portion of a property under eminent domain in order to use it for some public project. An example would be easement by condemnation of a strip of a property for a new highway.
5. Easement by prescription can forcibly create a right to property.Suppose that a property owner, whether he has access or not in another way, chooses to create a drive across the property of another and uses it exclusively to enter his property.
Times vary by state, but after a certain number of years, this person might be able to claim an easement by prescription. Generally for this to happen, the use of the property must have been without the permission of its owner, but visible and open to the knowledge of the owner. Thus, by not stopping this access, the owner could be forced to allow the easement by prescription.