A biodegradable product is a product that has been created in a way to allow for biodegradation. For example, many cleaning products may contain microplastics that end up getting washed down the drain without you even knowing about it. Although some products may use the terms "Biodegradable" on their products, this doesn't necessarily mean that the whole product is biodegradable, in fact, in most countries, the law states that for a product to be labelled as biodegradable it only has to have one biodegradable ingredient, and that ingredient can account for a minimum of 5% of the total product.
Dependent on where you live, you will want to check the local laws to get a better understanding of what constitutes as biodegradable and if any other labels may be used such as "Readily Biodegradable" or "Whole Product Biodegradable".
With this in mind, we also need to remember that the plastic bottles that most cleaning products come in are not biodegradable If you are looking to reduce the amount of plastic you use, you can attempt to bulk buy versions of the cleaning products that you use. This combined with keeping some of the single-use bottles you have to use as refillable bottles.
A biodegradable formula consists of ingredients within the said product being able to be broken down (biodegraded) in a reasonable amount of time. In most cases, this will constitute around 30 days / 1month. It is always best to check the ingredients of the product to ensure there are no chemicals as some companies may claim their products are "biodegradable" when they are not. This is a slight loophole that is taken advantage of as technically everything is biodegradable it's just the difference of being biodegradable in a short period, such as 1-4 weeks or thousands of years.
These cleaning products will likely contain things such as lemon juice and or baking soda or other natural compounds that can easily be broken down by the environment.