Well a Silent Mutation does not affect anything so it isn't bad so its a good mutation.
The mutation may be passed on to an offspring. Depending on the mutation, it may have no effect, or it could be lethal.
It can have absolutely no affect, a bad affect, or even a good affect.*Deletion and Addition are frameshift: most harmful.
More varity in a population
A point mutation, in which one nitrogen base in a codon is substituted for another, may have no effect on an organism. This is true if the base substitution does not change the amino acid that the codon represents, or if the mutation occurs in a non-critical location in the protein so that the protein's structure is not changed significantly and the protein is still able to function.
A deleterious mutation has a negative effect on the phenotype, and thus decreases the fitness of the organism. (A harmful mutation)
The location of the mutation within the genome, the type of mutation (e.g., missense, frameshift), and its effect on gene function or protein structure typically determine the magnitude of a mutation's effect. Additionally, the degree to which the mutation disrupts important cellular processes or regulatory mechanisms can also influence its impact.
No one knows what effect a mutation may have. Most are not viable.
If a particular mutation occurs in nature and proves to be beneficial, it can change the entire species to begin to have the same mutation and thus the same good trait. A creature with a mutation that say, gives it a longer tail (and chicks dig a long tail) than he will mate and that mutation will allow his genes to pass on.
If the point mutation does not change the protein to be translated in the 3-letter sequence, then it will have no effect on the gene's function.
The main question to consider when evaluating the effect of a mutation is how it alters the organism's phenotype or function. This involves assessing whether the mutation impacts protein structure or function, gene regulation, or any other biological processes that could affect the organism.
Some mutations can be deadly, harmful, or have no effect. Correct, not all mutations are harmful. Some mutations could even have a positive effect and help the creature adapt.