1) Sell shares short. Call your broker and say "sell short 300 shares of XYZ at (say) 40". Your broker will attempt to borrow the shares from another firm (or, conceivably, from an account w/in his own firm). Assuming he is able to do so, he'll then sell them and you receive the proceeds of the sale. If the share price subsequently moves up, you suffer a loss; if the share price subsequently moves down, you profit.
2) Buy put options. Call your broker and say "buy 3 (say) December XYZ 40 puts at the market". This is a purchase of the guaranteed right to sell shares of XYZ at 40, no matter where the share price may go, up until the 3rd Friday in December. You pay for this right, of course, so, in order to profit, the share price must decline more than a few points in order for you to profit. If the share price does not do so by December, you might lose your entire investment. Option buying should NOT be attempted by those who do not understand the pricing mechanism of options. There are any number of excellent books on the subject, the best being "Options as a Strategic Investment" by Larry McMillan.
The occasional way. There may be an ETF or ETN that deals in the shares/commodities you wish to short. These are usually, but by no means always, labelled 'short' or 'ultra-short' Blah-blah Fund(s). If the ETF is labelled 'short'/'ultra-short', then **buy** the shares of the ETF if you are looking for the share price of XYZ to decline. If **not**, sell the ETF shares short (much easier, as a rule, than selling stock shares short).
Good trading to you!
thanks I understand options, back in the 70’s I begged my boss to loan me 5k so I could buy silver options. He wouldn’t, silver was at 5.75 and went to 60. Man I was pissed.