Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
From what I’ve heard most women in fitness industry would use low doses of gh/anavar/primo and cutting drugs like clen and t3. These drugs won’t give women side effects like trenbolone or dianabol will if used responsibly. Yet I’m sure the best female weightlifters probably don’t care too much and too damage their body a bit. I think this study juse shows how easy it is to get caught with dbol/deca like someone posted above. Yet I think test/anavar/gh are used by pretty much everyone and if used correctly you won’t catch them with it. These drugs can also all be had by prescriptions so you can get really high quality unlike relying on UGL labs which usually have weak gear.
This strongly depends on the type and amount of actual substance and the person using them. Steroids can remain detectable in your system anywhere from 1 week to over a year after use. For the most popular steroid like nandrolone decanoate, it could be detected up to the year or even more in certain cases. But in most cases between 3-6 months is commonly sufficient for injectable testosterone. Luckily, for steroid users, the cost of a steroid test is very expensive (around USD 250-300) and hardly ever done. If you are being tested for “drugs” 99% of the time a steroid test is not done. Random tests for college sports will test for them though (the cost is probably the reason why they are random). People usually worry more than they should though. Even though a drug “can” be detectable, a lot of times they aren’t. So, mostly only professional sportsmen should be concerned and look for the “windows” when the substance is not detectable but still produces results.