Depending on what their needs, requirements, urgency, and budget might be, it may be a relatively simple matter, or it may take some real planning and time to get it done.
Obviously it could be as simple as putting in a temporary ramp, but what does the homeowner or tenant want - and what do the local codes or property owners association have to say on the matter of ramping? Can it be done as a temporary improvement - if that's what the client wants - or does it have to be done as a permitted and inspected structure?
Is the objective just to provide a way to reach the entrance safely and easily from the driveway or walk, or are there other expressed desires such as aesthetics, size, materials, surface, and ease of access and use?
What is the length of the proposed ramp from the bottom to the top, and how much distance does it need to cover? There is an effective limit to how much lift they can provide and still be usable so make sure that a ramp is the appropriate solution.
Then there's the matter or what it's made of and whether it can be substantial enough to serve your client.
You may want to consider an alternative - again depending on what the client wants, how much time is available for you to do the construction before it needs to be used, what building requirements may need to be met, and the length of time (if known) that it needs to last.
Rather than a temporary measure, you may want to consider - and discuss with your client - building a permanent inclined walkway to cover the desired distance in a straight line, gently curved, or switchback style. That walkway can have a concrete or brick surface, and it can be designed with planting areas along either side depending on how much space is a available to create and deliver it.
When the inclined walkway is done, it can potentially be much longer and rise a greater distance a traditional ramp. It can also looks like it is a normal part of the home - designed as a landscaping feature as much as being a function ramp. It can be an extremely attractive and desirable addition to the home.