An explanation of their different uses.
The table used for spell casting and holding your ritual tools is called an altar. It is invariably the focus of religious ceremonies.
Altars can be set up where space is available, and you do not need expensive fancy tools to practice Witchcraft. It is perfectly acceptable to use whatever fits your needs and what suits your pocket.
Rookies and Adepts alike forget to collate the tools and materials necessary for their spells or rituals. To avoid losing focus during your ceremony, be sure to have everything you need before you begin.
An altar does not need to be elaborate. Windowsills, your bedside table, a shelf, a small table, or even a surface often used for other things are all valid. The latter is beneficial if you are short on space or necessity forces you to practice in secret. For example, you could use the top of a dressing table or a cedar chest. Place an altar cloth on it or any piece of fabric dedicated to the Craft, and hey presto! Instant altar!
If you are lucky enough to practice outside, a tree stump or a large flat rock is ideal. If anything, these natural surfaces will add potency to your rite.
Broom closet witches may also benefit from a portable altar that can be stored away out of sight when not in use. A sturdy shoe box makes excellent camouflage, and a bandana makes an ideal altar cloth. If you dedicate it to be used as an altar cloth, from that point on, it is no longer a bandana.
Over time as you practice and develop, you may wish to have elaborate, bespoke altars displayed permanently in your home. The advantage of hand-carved altars is that intent and focused energy was invested in their creation. As a result, it will feel as if you are standing “between the worlds” when you use it. Ancestor altars with photos, ashes, and heirlooms from deceased loved ones are ideal for such displays.
Other types of altars include seasonal ones that mark the Wheel of the Year. If your practice does not have the worship of deities or is otherwise non-religious, this may not apply to you. For Wiccans and other pagan denominations, this constitutes a large part of their Craft. Witches and spellcasters of all types are more likely to have nature altars full of pretty objects they have found on nature walks, such as rocks, stones, feathers, pieces of wood, pinecones, acorns etc.
Altars are deeply personal, so if a specific configuration feels right to you, then do it. Let your intuition guide you.