Choose the sample space before drawing
Numbers can represent tickets, positions, measurements, codes, or game calls. Those uses start with different rules. A single winner is one label from an interval; a test sequence can repeat labels; an assignment needs each label only once. The correct page is determined by what may happen after one value has appeared, not by the fact that every output contains digits.
Replacement changes the probability
With replacement, every draw restores the whole range. Five draws from 1 through 20 can therefore show 3 twice. Without replacement, selecting 3 leaves 19 values for the next draw, which is appropriate for seats, prize winners, or numbered tasks. Lottery lines are also without replacement, but their sorted presentation hides selection order because only the combination matters.
Representation is part of the rule
A decimal is rounded to a stated number of places; a percentage is a label out of 100; a PIN keeps zeroes at the front; a bingo call maps an integer to a lettered column. These are not cosmetic variations. Dropping a leading zero changes a code, while interpreting a random percentage as a measured probability makes a claim that no draw can support.
A checkable selection example
For six distinct workshop stations numbered 1 through 50, use the unique-set rule: a possible result of 14, 2, 41, 28, 35, 9 assigns no station twice. For five independent software test events, the repeated-integer rule is better because 3, 17, 3, 9, 20 is valid. A six-from-49 lottery line is a third case: it needs unique balls and a game-specific rules check.
What the tools cannot decide
A browser draw cannot verify eligibility, certify a public contest, predict a lottery, retain an official record, or create a security policy. Set the population, any exclusion rule, and the consequence of a redraw before using a result. When an outcome affects money, access, prizes, or another person, save the inputs and the stated procedure alongside the result.