Going long means establishing or increasing a bought position. For a spot cryptocurrency or ordinary futures contract, the usual intention is to benefit from rising prices or to offset an existing exposure that loses when prices rise.
The order must actually execute
Placing a buy order is an instruction, not confirmation that a long exists. A limit order may remain unfilled or fill only partly. The executed quantity and prices determine the resulting exposure and average entry.
In derivatives, a buy can instead close an existing short. Position mode and open/close instructions determine its effect. A buy that exceeds a short position may reverse the account into a long under a netting system, unless an applicable reduce-only instruction prevents that.
Plan the position as well as entry
Check the instrument, quantity, settlement currency and collateral before interpreting a trade as long exposure. Buying an option means being long that option; buying a put need not mean expecting the underlying to rise.
A favorable forecast is not a guarantee. Entry costs, funding, price gaps and margin constraints can affect results, and a leveraged position may close through liquidation before the anticipated move occurs.